Question

Розв'яжіть рівняння:

1) 14x2-(2x-3) (7x+4)=14;

2) (8x+10) (3-x)=(11-2x) (4x+5)-5;

3) (x+6)(x-3)-(x+3)(x+9)=9.​

Answer 1

Ответ:

Объяснение:

1) 14x²-(2x-3) (7x+4)=14;

14x²-14x²-8x+21x+12 = 14;

13x = 2;

x=2/13.

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2) (8x+10) (3-x)=(11-2x) (4x+5)-5;

24x-8x²+30 -10x = 44x+55-8x²-10x - 5;

24x-44x = 55 - 5 -30;

-20x = 20;

x=-1.

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3) (x+6)(x-3)-(x+3)(x+9)=9.​

x²-3x+6x-18 - x²-9x-3x-27 = 9;

-3x+6x-9x-3x = 9+27+18;

-9x = 54;

x=-54/9;

x=-6.

Answer 2

Ответ:

1. $x=\frac{2}{13}$

2. $x=-1$

3. $x=-6$

Объяснение:

$1) 14x^2-(2x-3)(7x+4)=14\\14x^2-(14x^2-21x+8x-12)=14\\14x^2-(14x^2-13x-12)=14\\14x^2-14x^2+13x+12=14\\13x+12=14\\13x=14-12\\13x=2\\x=\frac{2}{13}$

$2) (8x+10)(3-x)=(11-2x)(4x+5)-5\\24x+30-8x^2-10x=44x-8x^2+55-10x-5\\-8x^2+14x+30=-8x^2+34x+50\\-8x^2+14x+30+8x^2-34x-50=0\\-20x-20=0\\-20x=20\\x=\frac{20}{-20}\\x=-\frac{20}{20}\\x=-1$

$(x+6)(x-3)-(x+3)(x+9)=9\\x^2+6x-3x-18-(x^2+3x+9x+27)=9\\x^2+3x-18-(x^2+12x+27)=9\\x^2+3x-18-x^2-12x-27=9\\-9x-45=9\\-9x=9+45\\-9x=54\\x=\frac{54}{-9}\\\\x=-\frac{54}{9}\\\\x=-6$